On my first server back in 1.4 they had an IRC channel hooked up to their chat, so not only could you see the chat, but you could talk to the server as well.

However I'm strongly against this. Any can log into the IRC with a staff's name and start trolling around. It would also mean that a staff would have to be in the chat to ban/kick people being abusive, as well as banning them on the server. It also means people can have a bunch of throwaway accounts they can use to chat with even if they are banned, it's not like MC where you have to pay to have an account, as long as you have a dynamic IP you can create a new account and keep logging in. I can already foresee people logging in under another persons name and messing around.

It'll be a lot easier if it's read only (or automatically mute everyone who joins, then have a list of let's say trusted and up who have voice in the chat), bit tbh I don't see why you'd want to see the chat without talking.